On S390x we don't want to go through the hassle of emulating real existing
hardware, because we don't need to for running Linux.
So let's instead implement a machine that is 100% based on VirtIO which we
fortunately implement already.
This patch implements the bus that is the groundwork for such an S390x
virtio machine.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>